Specify heigh of images in css doesn't work - html

Question

I am currently working on a django blog. However, I am experiencing some difficulties with the size of the post thumbnails. Here's a picture:
What I marked in yellow is how the image should be filling the space. The width is fine, but the heigh isn't working well as you can see.
Here's the code:
{% extends 'base.html' %}
{% load static %}
{% block content %}
<style>
img {
height: 100%;
width: 100%;
}
</style>
<!-- Post-->
{% for obj in object_list %}
<div class="row d-flex align-items-stretch">
{% if not forloop.first and not forloop.last %}
<div class="image col-lg-5"><img src="{{ obj.thumbnail.url }}" alt="..."></div> #Here's the image
{% endif %}
<div class="text col-lg-7">
<div class="text-inner d-flex align-items-center">
<div class="content">
<header class="post-header">
<div class="category">
{% for cat in obj.categories.all %}
{{ cat }}
{% endfor %}
</div>
<a href="{{ obj.get_absolute_url }}">
<h2 class="h4">{{ obj.title }}</h2>
</a>
</header>
<p>{{ obj.overview|linebreaks|truncatechars:200 }}</p>
<footer class="post-footer d-flex align-items-center"><a href="#" class="author d-flex align-items-center flex-wrap">
<div class="avatar"><img src="{{ obj.author.profile_picture.url }}" alt="..." class="img-fluid"></div>
<div class="title"><span>{{ obj.author }}</span></div></a>
<div class="date"><i class="icon-clock"></i> {{ obj.timestamp|timesince }} ago</div>
<div class="comments"><i class="icon-comment"></i>{{ obj.comment_count }}</div>
</footer>
</div>
</div>
</div>
{% if forloop.first or forloop.last %}
<div class="image col-lg-5"><img src="{{ obj.thumbnail.url }}" alt="..."></div> #Here's the image
{% endif %}
</div>
{% endfor %}
</div>
</section>

Answer 1

It is <img>'s default behaivor to fill the whole width and height, often losing its aspect ratio.
The fact that it did not happen in your case, most likely is because you set object-fit: contain somewhere in your css.
You either remove object-fit: contain setting, or you can use
img {
height: 100%;
width: 100%;
object-fit: fill !important; # fill is the default value.
}